This invention is directed to an improved hand-held hair treatment device which can be used for drying, shaping or styling hair. More particularly, this invention is directed to a novel hand-held hair treatment device which contains a means to infinitely vary the airflow velocity from a concentrated blast directed to a small area to a wide gentle breeze directed to a large area without changing the fan motor speed. This device enables the user to operate the means to vary the airflow velocity during operation of the device and thus to style, shape and dry hair in an efficient, convenient manner.
Hand-held hair treatment devices of a variety of designs and styles for styling, shaping and drying hair have been marketed. Typically, these devices include an electric heating element and means for controlling the electric current through the heating element to control the amount of heat generated. Hair dryers also typically include a fan or impeller for drawing in external air through an air inlet, passing it over the heating element and discharging it through an air outlet which comprises an aperture for directing the air against the hair to the area to be dryed, shaped or styled. Various attachments on the air outlet also can be used to direct the air and control its flow, temperature, volume and/or velocity through the air outlet. This is inconvenient since the operator must interrupt the treatment to change attachments when a change in, e.g. airflow velocity is desired.
In using hair dryers for styling, shaping or drying, it is desirable to be able to direct the stream of heated air of various temperatures and velocities to large or confined areas of the hair. When directing the air to a large area, it is necessary, in the known devices, to utilize a relatively large mass of air, as a result the velocity of the air stream which is directed to the hair is relatively high. This is undesirable because the high velocity of the large mass of air disturbs the styling and has a tendency to compact the hair.
Attempts have been made to overcome these problems and control the airflow in hand-held hair dryers without changing motor speed. None of these attempts have, however, resulted in a means for controlling airflow by using a pair of hinged trap doors in the airflow conduit near the air outlet which are controlled from the outside of the dryer while the dryer is in operation.
Soler, et al., U.S. Pat. No. 4,097,722 utilize a damper in the air outlet conduit to adjust the area of the air discharging orifice. The damper is pivoted in the conduit downstream of the air heating element and is selectively movable between first and second positions providing maximum and minimum orifice openings for producing a dispersed and a concentrated airflow, respectively. There is no means shown in providing an infinite variation of orifice openings between the maximum opening and the minimum opening.
Levy, et al., U.S. Pat. No. 4,019,260 disclose a hair styler and dryer in which the airflow is caused to pulsate by a variable flow impedance which is formed by an elongated sheet pivotally mounted along a normally vertical transverse axis of the air outlet conduit.
The Levy, et al. device is used for fluffing hair and has no structure for controlling the airflow by varying the opening size in the air outlet conduit.
Ono, U.S. Pat. No. 3,947,659 discloses a hair dryer with vapor ejection means. The vapor is ejected through a nozzle in which the outlet opening size is controlled by a shutter.
Thus, none of the hair dryers and stylers existing satisfactorily provides a means for convenient control of the airflow velocity at infinite variations between the maximum and minimum openings in the air outlet of the device used without changing the absolute air volume.